Compound clarifier



June 12, 1945. w. E. GEISSLER COMPOUND CLARIFIEB.

Filed Dec.

1, 1941 3 Sheets-Sheet l INVENTOR VV/lL/fl/ E. 65/554 5/? H. 8W

ATTORNEY AwWw-i v a June 12, 1945. w. a'caElssLER COMPOUND CLARIFIER.

3 Sheets-Sheet 2 Filed Dec. 1; 1941 INVENTOR V/LL/HM E. 65755151? EATTORNEY Paramecium 12, 1945 UNITED sTAres PATENT OFFICE COMPOUNDcmarr'mn William E. Geissler, Osslnlng, N. Y., asslgnor to The DorrCompany, New York, N. Y., a corporation of Delaware 7 ApplicationDecember 1, 1941, Serial No. 421,171

14 Claims.

The general object of the present invention is to provide improvedapparatus for use in the continuous clarification of liquids bysedimentation and decantation, and particularly for use in the compoundclarification of two liquids received from different sources and havingdifferent char acteristics in a single multitray clarifier structure.

More specifically, the object of the invention is to provide a singlemultitray clarifying machine adapted for use in the compoundclarification of the primary juice and secondary juice extracted fromsugar cane in initial and subsequent portions, respectively, of a sugarcane milling train or circuit of the usual type, such secondary juicehas a lower sugarcontent and is of lower purity and ordinarily is moredifiicult to clarify though smaller-in volume than the simultaneouslyproduced primary juice.

Now, and in recent years, the clarification method, commonly called"compound clarification which is disclosed and claimed in the PetreePatent No. 1,625,680, granted April 19, 1927, has been in extensive,widespread and successful use in clarifying sugar cane juice; andgenerally regarded as the most efficient and desirable methodpractically available for the purpose. That method comprises twoseparate continuous clarifying actions in each of which clarified liquidis separated from mud, which includes the solids separated My improvedmultitray clarifiei y comprises a plurality of superposed clarifyingcompartments and two receiving chambers respectively above and connectedto upper and lower groups of said compartments, 'to thereby form twoseparate clarifying units, each including one of said chambers and theclarifier compartment or compartments connected thereto, and alsocomprises mud rakes working in the different compartments of the twounits and carried by and forming a part of .a common rotating structureincluding a vertical column centrally disposed in the clarifier saidrotating structure preferably includes agitat ing elements in thereceiving chambers of the two units which serve to flocculate the liquidtherein prior to its flow into the corresponding clarifyingcompartments. 1

My improved clarifier may include various arrangementsof thetworeceiving chambers and associated clarifying compartments, and of theconduit or flow path provisions for the passage of from the clarifiedliquid subjected to the clarifying action. Furthermore, 'the liquidsubjected to one of the two clarifying actions is a mixture includingthe clarified liquid product 'of the other action and the relativelyrich primary juice sepa rated from the sugar cane in an initial portionof the milling circuit, and the liquid subjected to the other clarifyingaction includes the relatively weak juice extracted from the sugar canein a secondary portion of the milling circuit, and also ineludes the mudproduced in the clarification of the-mixture including the primaryjuice. In compound clarification as heretofore practiced, the twoclarifying actions have been effected in separate clarifiers, each ofwhich is customarily a multitray clarifier. By the use of a singleclarifier constructed in accordance with the present invention, in lieuof the two separate clarifiers heretoforerequired for compoundclarification. I simplifythe clarifying operation, and reduce theconstruction, operation and maintenance costs of the. apparatus requiredfor the clarification ofa given .amount of cane sugar Juice, and alsoreduce the floor and housing space required;

liquid from each receiving chamber into the associated clarifyingcompartments.

In a. preferred form of the present invention for I use in clarifyingsugar cane juice, the secondary juice receiving chamber is located inthe upper portion of the clarifier, and is of a diameter less than theclarifier diameter, and the primary juice receiving chamber comprises acentral portion beneath the secondary receiving chamber and an annularportion surrounding the secondary chamber. This preferred arrangement ofthe two receiving chambers contributes to and facilitates the provisionof means oi. desirable form for the removal 01' scum from the tworeceiving cham-' vantageously include provisions for independentlyraising and lowering the discharge and of the connection, such as arecustomarily employed in regulating the relative overflows of clarifiedjuice from different clarifying compartments of an ordinary multitrayclarifier. Such clarified juice overflow connections serve the specialtpurposein m impr ed clarifler, of insuring that in normal operation,approximately the same hydrostatic pressures in the two clarifying unitswill exist at every liquid level common to the .two units. Themaintenance of such common hydrostatic pressures in the two unitseliminates the possibility that in normal operation a part1,-

tion separating adjacent compartments of the two units will be subjectedto the harmful mechanical stresses to which it might be subjected ifrelative liquid levels in the two units varied substantially. Themaintenance of such common pressures also minimizes the tendency to flowfrom one unit into the other through a joint space between the centercolumn of the rotating structure and the margin of the central openingin a partition separating adjacent compartments included in differentunits.

Advantageously I provide a joint seal between the rotating structure andthe partition separating the lower compartment of one unit from asubjacent compartment of the other unit, which is normally effective toprevent flow from one compartment into the other, but which operateslike a safety valve to permit such flow on the development of anabnormal differential pressure, such as may occur in filling or emptyingthe clarifier at the beginning or end of a grinding season, or in thecourse of a clarifier cleaning or repair operation.

The various features of novelty which characterize my invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,however. its advantages and specific objects attained with its use,reference should be had' to the accompanying drawings and descriptivematter in which I have illustrated and described preferredembodiments ofthe invention.

Of the drawings:

Fig. 1 is a flow sheet diagrammatically illustrating the use of apreferred form of my improved clarifier in association with a sugar canemill of conventional type;

Fig. 2 is a plan view of the clarifier shown diagrammatically in Fig. 1;

after leaving the rolls A. The liquid expressed from the cane by therolls A and primary mill A passes into the primary juice collection boxB. The juice passes from the box B through a pipe I to juice treatingapparatus C in which the juice is heated and limed in the customarymanner. and from which the juice passes through a pipe 2 to the primaryjuice receiving chamber D of a multitray clarifler E. The juiceexpressed from the cane by the secondary mill A, is collected in a juice,box 18 from which juice passes through a pipe 3 to a secondary juiceheating and liming Fig. 3 is an elevationof the clarifler shown in Vciated with said central column;

Fig. 6 is a partial section on the line 6-8 of Fig. 3;

Fig. 7 is a somewhat diagrammatic sectional elevation, and Fig. 8 is aplan, of a modified form of clarifier; and

Fig. 9 is a somewhat diagrammatic sectional elevation of a third form ofa clarifler.

In Fig. 1 I have illustrated diagrammatically the use of a preferredform of the present invention in connection with a sugar cane mill'whichis of conventional type, and which is associated with my improvedclarifier and with juice heating apparatus and a source of macerationwater, by piping of the character commonly used in associating a sugarcane mill with apparatus for the compound clarification of sugar juice.

As shown in Fig. 1 the sugar cane mill circuit includes a pair ofdisintegrating rolls A, and four three roll grinding mills, A, A A and Athrough which the sugar cane passes successively device CA from whichthe juice passes through a pipe 4 to the secondary juice receivingchamber d of the clarifler E. Juice expressed from the cane by the millA is collected in a juice receiving box B and passes from the latterthrough a pipe 5 back to the mill circuit where it is discharged asmaceration liquid on to the cane passing from the primary mill A to thesecondary mill A. Juice expressed from the cane by the mill A iscollected in the juice receiving box 3*, and is returned to the millcircuit for use as maceration liquid by a pipe 8, which discharges ontothe cane passing from the secondary mill A to the third mill AMaceration water is discharged by a pipe I onto the 'cane passing fromthe third mill A to the fourth mill A.

As shown in Fig. 1, secondary juice clarified as hereinafter described,passes from the clarifler E through a pipe 8 into the juice box B, sothat the pipe I carries a mixture of unclarifled primary juice andclarified secondary juice away from the juice box B. The primary mudremoved from the primary clarifying unit of the clarlfler E ashereinafter described, is passed through a pipe 9 into the secondaryjuice receiving box B, and the pipe 3 thus carries away from thesecondary juice box 2B a mixture of unclariiled secondary juice receivedfrom the mill .A with the mud separated from the primary juice in theclarifier E.

As shown best in Fig. 3, the secondary juice chamber 11 is separatedfrom the receiving space D by a pan-shaped partition member 1 smaller indiameter than and axially disposed in the shell or tank of the clariflerE. The partition I has a dished bottom and an uprising rim or peripheralportion f, and is carried by truss-like supports 1 which extend radiallyinward from the peripheral wall of the clarifler E into engagement withrim 1', and thus do not interfere with the hereinafter mentioned mudrakes and scum removing means. A dished partition F generally parallelto and spaced downwardly from the bottom wall of the partition f, formsthe bottom wall of the receiving chamber D. The partition F extends toand is welded or otherwise attached at its periphery to the cylindricalwall of the tank E. The primary juice receiving chamber D thus includesa portion directly beneath chamber d. and an annular portion surroundingthe chamber 11 and extending between its vertical wall I and thesurrounding wall of the tank E.

A series of dished partitions F, FEE and F generally similar in form tothe partition F and each attached at its periphery to the tank shell,divides the portion of the tank space beneath the chamber D into threesuperposed primary juice clarifying compartments G, G G and twosecondary juice clarifying compartments g and 9 The compartment G isdirectly beneath the re ceiving chamber D, and the compartment g isdirectly above the. conical bottom wall of the tank. The partition Fseparates the bottom 2,877,875 compartment (3- of the primary juiceclarifying I settled sludge or mud towards the center ofthe receivingchamberor clarifying compartment in which it works. The rotatingstructure also includes mud rake arms H working mud accumulating in thebottom compartment 9 toward the central mud outlet E in the bottom wallof the The shaft H also supports and rotates floccu-' lating panels orgrids H" and H in the receiving chambers d and D, respectively, and scumremoving sweeps H and H at the inner and outer sides of the upper edgeof the uprising rim portion f of the wall of the receiving chamber (1.

The sweeps H' and H are adapted to work scum into outer and innerportions of a common scum channel or trough I, which extends from thetank periphery inward across the annular outer portion of the chamber Dand across an outer portionof the chamber d. Curved arms H carried bythe shaft H in the chamber d, and just short enough to clear the innerend of the cum channel I, work scum from the central portion of thechamber 11 into the path of the sweeps H The rotating structureincluding the shaft H is rotated at a suitably low speed by mechanism H"above the tank E, which may be of the type customarily employed torotate the mud raking structure of the multitray clarifier ofconventional type, and hence need not be further described herein.

In the preferred clarifierconstruction illustrated. juice is fed fromthe receiving chambers D and d to the corresponding subjacent clarifyingcompartments by separate feed channels within and extendinglongitudinally of the tubular shaft H. Thus, as shown in Figs. 3 and 6,vertically extending partitions J in the upper portion of the hollowshaft H separate two primary juice distribution channels K at oppositesidesof the shaft, from a central secondary juice channel L.

Iii. Big. 5 Ihave illustrated sealing provisions which may be employedto prevent'leakage flow between the receiving chambers D and d throughthe joint between shaft H and the margin of the central opening in thepartition element f. The sealing provisions shown in- Fig. 5 comprises aflexible washer or gasket member N of cup leather form, mounted in anannular support N carried by thepartition element 1 and having aflexible edge bearing against the periphery of a metallic bearing ring Nwelded on the shaft H. The

character of the sealing provision just described is relativelyunimportant, since the pressure differential tending to produce leakagebetween the two receiving chambers will never be large andsome smallleakage between the chambers will do no real harm.

It is definitely advantageous, however, to prevent leakage under normalconditions, and to permit leakage under abnormal. conditions through thejoint between the shaft H and the partition F and for this purpose. Iadvantageously make use of sealing provisions of the type illustrated inFig. 4, Those provisions comprise a cylindrical member 0 attached to andforming a hollow uprising projection from the partition 1"", and whichsurrounds the shaft H from which it is separated by an annular space. Asshown, the member 0 comprises an out-turned flange portion 0' at itslower end, which has its peripheral edge welded to a cylindrical boot Fsecured to and depending from the partition F at the margin of thecentral opening therein. The upper endlof the member 0 extends into anair pocket (1 open at its lower end and closed at its upper end, betweenthe-shaft H and a cylindrical hood member 0 The latter is spacedoutwardly awayfrom the porticn of the member O which it overlaps, andhas an upper end portion of reduced diameter; which is welded to theshaft H.

The wall of the shaft H is cut away to form inlet ports K, one openinginto the upper end of each channel K from the portion of' the receivingchamber D between the walls 1. and F. Each channel K is also providedwith an outlet port K opening to the clarifying compartment G, and witha second outlet port K opening to the compartment G As shown, the portsK are simple openings'or windows in the cylindrical wall ofthe pipe H.Each port K however, is in register with a corresponding pipe section Krectangular in' cross section which is welded to and extends radiallyaway from the pipe H, The

pipes K extend through and support a cylindrical member M coaxial withthe pipe H and unit'- ing with the latter to form an annular channelthrough which mud passes from the compartment G'- into the lowerwportionof the compartment Gfias hereinafter explained. The pipe H is formedwith inlet port openings L' through which secondary juice passes intothe channel L from the secondary juice receiving chamber d, and withoutlet ports L which open from the channel into the compartment g.

Under normal operatingconditions. liquid flow over the top of the member0 in either direction between the chambers'cl and g is. prevented by airsupplied to the air pocket 0 by a pipe 0 at a suitably low pressurewhich is limited by bleed ports 0' formed in the wall of the pipe H at alevel below the top of the member 0 and above the bottom of the member 0Air bleeding through the ports 0 into the feed channel fier at the end"of such a period, there is a possibility that liquid will be passed intoor withdrawn from one of the two clarifying units much more rapidly thaninto or from the other. This might result, for example in making thepressure in the compartment g'- much higher than the pressure in thecompartment G and thereby subject the Partition F to destructivestresses, if no means were provided for limiting the maximum value ofthe diflerential of said pressures. I

, The sealing provisions shown in. Fig. 4 are adapted to suitably limitthe maximum of value ofsaid differential. As will be apparent, as soonas the pressure in one of-the two compartments exceeds that in the otherby an amount corresponding to a liquid head equal to the distancebetween the upper edge of the member and the lower edge of the member0", liquid will begin to new through the space 0 from one compartmentinto the other, and if the flow capacity of the flow path including saidspace, is suflicient for the purpose, as it may well be, it will actlike a safety valve to prevent further increase in the pressuredifferential between the two compartdown into the compartment 9'. Mudseparated from the primary juice in the chamber D is also relativelysmall in amount and may be worked by the mud rakes H either through theports K into the feed channels K and thence into the compartments (3 and(3 through the ports K and K or directly into the compartment G throughthe joint space between the'partition F and shaft H. As shown, themember H is surrounded by a bearing ring or collar P immediately abovethe ports K, which is engaged by guide means P secured to the dishedpartition F and centering the shaft H. The guide provisions P need notbe of a character to interfere with the passage of mud through the jointbetween the partition' F and the member H.

Mud worked toward the center of the compartment G by the mud rakes Hpasses downward into the compartment G through the annular gamers intothe center of that compartment by the mud rakes H, passes downward intothe compartment 0' through the annular channel between the shaft H andthe depending center boot portion of the partition F The mud thusentering the compartment 9, along with the mud settling in thatcompartment, and the mud passing downward space between the shaft H anda depending-boot portion of the partition member F surrounding thecentral opening in the latter. As shown, the last mentioned boot extendsdownward into the annular space surrounded by the previously mentionedmember M. The latter guides the descending mud into the lower portion ofthe compartment G, and in conjunction with the tubes K keeps the Juiceentering the compartment (3: from the feed channels K away from the mudentering the compartment from the compartment G. Mud passing downthrough the member M, and mud worked into the center of the compartmentby the mud rakes H pass into the compartment G through the annularchannel between the shaft H and the boot depending from the partition Fat the margin of the central opening in the latter.

The mud rakes H work the mud received from the compartment G and mudsettling in the compartment G into an annular mud trough Q collectivelyformed by the member 0 and boot F which is of appreciably greaterdiameter than the shaft H, and is connected to the flange portion 0' ofthe member 0 at a distance appreciably below the partition F The modthus received in the trough Q passes away from the clarifier through anoverflow connection comprising a horizontal pipe section Q extendingfrom the trough Q outwardly through the shell of the clariiier E and anexternal uprising pipe section Q through the upper end of which mudoverflows into a mud box Q at a level but little below the liquid levelin the chamber D. The overflow level in the mud box Q may be adjusted bythe vertical adjust ment of a sleeve Q in telescopic relation with theu" per end of the pipe section Q Mud settling in the compartment a andmoved through the shaft H, is worked to the central outlet E in thebottom wall of the clarifler E by the mud rakes H", and passes away fromthe clarifler through a mud draw-oil. pipe R, which discharges into amud tank 3 The latter forms part of secondary mud handling apparatus ofknown type, which as shown in Fig. 1, comprises a rotary filter R towhich mud is moved from the tank R by a pump R and from which a pump Rwithdraws relatively clear filtrate and passes it into admixture withthe secondary juice flowing through the pipe 3 from the juice box 13 tothe secondary juice treating apparatus CA.

In the arrangement shown in Fig. 3, the juice clarified in each of thecompartments G and 0' passes into the compartment along with the mudfrom the compartment immediately above, though each of the clarifyingcompartments shown in Fig. 3 might have a separate feed inlet as do eachof the clarifying compartments of the clarifiers shown in Figs. '7 and8.

Clarified juice is withdrawn from the primary juice clarifyingcompartments G, G and 6 through overflow pipe connections S, El and Srespectively, each of which includes an uprising portion external to theclarifler E, discharging at its upper end into a primary juice overflowbox S. The discharge levels of each of said connections may bevertically adjusted in a known manner by an adjustment of the sleeve Sin telescopic association with, and, in effect, forming the upper end ofthe corresponding overflow connection. .The clarified juice passed intothe juice box S, is withdrawn from the latter through a pipe S fortransmission to the evaporating pans (not shown). Similarly, clarifiedjuice is separately withdrawn from the secondary juice clarifyingcompartments 9 and g through overflow connections T and T includinguprising portions which discharge at their upper ends into a secondaryjuice overflow box T. The discharge level of each of the overflowconnections T' and I may be adjusted by vertical adjustments of a'sleeve T forming the upper end of the overflow connection. Theclarified secondary juice passed into overflow box T passes from thelatter through the previously mentioned pipe 8 to the juice box B whichreceives primary juice from the rolls A and primary mill A. Each of theoverflow connections S, S S T and 'I' may receive juice through theusual circularly extending perforated pipe located in the upperperipheral portion of the corresponding clarifying compartment.

The intended operation of the apparatus collectively illustrated byFigs. 1 to 6 will be readily apparent from the foregoing statements ancexplanations. .As those skilled in the art will understand, with theapparatus illustrated in Figs. 1 to 6 the compound clarification methodcan be practiced in the same manner and to the same advantages, as ithas heretofore been practiced with apparatus including separate primaryjuice and secondary juice multitray clarifier. The use of the singleclarifler which I have devised in lieu of the two separate clarifiersheretofore required for compound clarification, gives a number ofpractically important advantages includ-- ing:

In general, the inherent cost or construction will be lower for myclarifier; than for the'separate primary and secondary clarifiers of thesame aggregate clarifying capacity, in respect to each In general, also,the use of a single clarifier constructed in accordance with the presentinvention, in lieu of the two clarifiers heretofore requiredfforcompound clarification, should reduce the operation and maintenancecosts by reducing the heat loss from the clarifying apparatus, byreducing the power consumption of the mud raking machinery, and byreducing the exclariiying compartments gaLand ga respectively. Juicepasses from the primary juice receiving chamber DAtc the clarifyingcompartments GA and GA, through feed conduits KA in the shaft HA as inthe construction first described. The feed conduits KA have their lowerends extended and provided with outlet ports KA for the passage ofprimary Juice from the chamber DA directly into the lowermost primaryclarifying compartment GA t Mud passes from the receiving chamber DA andfrom the clarifying compartments GA and GA. of the clarifier EA througha mud channel U, which comprises all of the bore of'the horizontal shaftHA not occupied by the feed conduits KA. Mud enters the mud channel Ufrom the chamber DA through inlet ports U, and en- ,ters said'channelfrom the compartments GA and GA through ports U and U respectively,

pense for labor and material necessary to maintain the clarifyingapparatus in operation.

While I regard the apparatus shown in Figs. 1 to 6 as embodying the bestform of my invention now known to me for practical use under ordinaryconditions, it will be apparent that'the general principles of thepresent invention-may be used and the major'advantages thereof may-beobtained, with clarifying apparatus quite different from thatillustrated in Figs. 1 to 6, and in Figs. 7 and 8 I have illustrated oneclarifier, and in Fig; 9 a second clarifier, which differ in a number ofrespects from one another and from the clarifier shown in Figs. Ito 6.

and passes out of the channel U into the compartinentGA through ports UThe shaft HA comprises an upper hollow section and a lower rod-likesection HA. The latter passes through -a central opening in the bottomwall of a conical mud pocket QA having its .Wall formed by a depressedcentral portion of the. partition FA Primary mud passes from the pocketQA through a pipe QA' to a mud pump V The clarifier EA shown in Figs. '7and 8 comprises many parts which are similar, or analogous to parts orthe clarifier first described, and which are designated so far asappears necessary in Figs. 7 and 8, by reference symbols diil'ering fromthose used in Figs. 1"to 6 to describe corresponding parts, only by theinclusion of a secand reference letter, -A or a. The clarifier EA- shownin Figs. 7 and 8 differs from the clarifier E first describedprincipally in the ,form and disposition of its receiving chambers DAand do; in the manner in which the secondary juice "is passed from itsreceiving chamber da into the associated secondary juice clarifyingcompartsions, and in details of its scum removing provisions.

The secondary: Juice receiving chamber do or the clarifier EA isannularin form extending between the cylindrical wall of the clarifier EA andwhich is external to the clarifier EA and discharges the mud through anuprising pipe QA into a hopper QA above and opening into the pipe 4A inwhich it mixes with the secondary Juice passing into the receivingchamber da.

Mud passes from the clarifying campartment ya into the compartment gothrough a central depending boot portion FA of the. interveningpartition member FA depending from the latter at the margin of itscentral opening.

In Figs: 7 and 8, the scum trough IA extends into the clarifier EA fromthe cylindrical shell thereof for a radial distance less than the radialextent of the chamber da. Scum is worked over the uprising portions faof the partition member fa from the primary receiving chamber DA,

and along the upper portion of the secondary receiving chamber da at theinner side of the scum trough IA, into the path of movement of ments 0aand ya, in its mud handling provi-,

the uprising portion fa of a partition member fa, which is,oi angle-barcross section and has its bottom. portion extending intc,engagementwith, and welded, or otherwise secured, to the cylindrical shell of theclarifier EA. The chamber DA separated from the 'chamberda by thepartition .fa, comprises a central cylindrical por-' tion at the innerside of the partition Ia and an annular portion underlying the partitionfa.

Secondary Juice passes from the chamber do to the clarifying compartmentya and ya through piping LA and shown as. comprising a vertical conduitexternal to the shell of the clarifier EA which .receives juice from thechamber da through a connection LA, and is provided adJathe scum sweepsHA by curved scum sweep arms HA". The joint between the shaft rodportionf HA and the margin of the opening'in the partition FA throughwhich said portion passes, is sealed by sealing provisions" NA which maybe similar iniorm and .type to those illustrated in "Fig.5.

\ Except in respect to vdilferences mentioned above, theclarifier EA maybe similar in construction and operation to the clarifier EA firstdescribed.

- The clariflerEB shown in Fig. 9 comprises many features similar tocorresponding features of the clarifier shown in Figs; 7 and 8. Theclarifier EB diifers primarily from theqclarifiers previously described,in that its secondary juice receiving chamber db is located below thepartition FIE;

- separating the lowermost primary juice clarifying compartment GB fromthe upper secondary juice clarifying compartment 9 As shown, the chamberdb isisurroundedby a cylindrical wall coaxial with the tank or shellofthe clarifier EB, but of much masher-diameter.

2). The lower seccelves Juice to-be clarified as Well as mud, from .thecompartment ob through the boot FA de- The chamber db opens at ts lowerend directly into an underlying portion 1 the compartment ondaryclarifying compartment obi of Fig. 9 repending from the partition FAseparating the two compartments.

Primary juice passing from the feed chamber DB, which occupies theentire'horizontal cross section of the clarifler EB, tank or shell abovethe partition F3, is distributed to the sublacent clarifyingcompartments GB, GB and GB, and

mud is passed from the chamber DB and from which forms a mud pocket QBhaving its outer wall formed by a corresponding portion of the shell ofthe clarifier EB. Primary mud passes from the mud pocket QB through apipe QB into a mud tank QB from which the mud is moved,

by a pump VB and its discharge pipe QB into the feed pipe 43 throughwhich'secondary juice admixed with the primary mud, is passed into thesecondary juice receiving chamber db.

The pressures in the portions of the primary and secondary juiceclarifying units adjacent but at opposite sides of the partition F3, areadapted to be substantially equalized in normal operation, by theclarified juice overflow provisions QA which may be identical inprinciple with those shown in Fig. 1, and in Figs. 7 and 8.

Scum rising to thetop of the liquid in the chamber DB of Fig. 9 is movedinto a scum pocket within and adjacent the shell of the clarifier EB bycurved sweepers hb. A valved scum draw oif pipe W opens into theuppermost portion of the receiving chamber db, through which scum may beperiodically removed from aid chamber.

The three clarifier forms shown in sectional elevation in Figs. 3, '7and 9 are generically alike in that each discloses a multitray clarifierincluding two clarifying units adapted for use in carrying out compoundclarification, and each comprising a receiving chamber and a plurality.of associated clarifying compartments.

Each of the three forms permits of the attainment of all of the generaladvantages obtainable by use of a single clarifier structure in lieu ofthe two separate clarifiers heretofore required for compoundclarification including in particular the advantage of a single mudmovtion of the liquid in the receiving chamber D to which movementsrelative to the supports f are given the liquid by the scum sweeps Habove the supports 1* and the mud rake arms H and flocculation arms 1-!which move through the zone beneath thebrackets f.

The three forms of apparatus shown in Figs. 3,? and 9 diiferspecifically in respect to the manner in which juice to be clarified isfed into the clarifying-compartments. Thus, inFig. 7 juice to beclarified is fed to each of the clarifying compartments GA', GA, on andan along a new path separate from the flow paths through which each ofthose compartments receive settled solids from the compartment above it.In the form shown in Fig. 3 the lowermost compartments G and g of thetwo units each rerelatively low density, their volume may exceed theaggregate volume of properly thickened mud and properly clarified juicewhich can be withdrawn from the compartment GA through its mud outlet QAand clarifying juice outlet 8A In such a case, therewill be back flowfrom the compartment GA through the feed inlet port KA, with the resultof some disturbance or upset in the clarifying performance of thecompartment GA Such back flow from the compartment G and resultantdisturbance in, the operation of compartment G will not occur in theoperation of the clarifier shown in Fig. 3 under similar operatingconditions. With different conditions tending to lhigher density andlower volume of the solids separating from the clarified liquid in thecompartments G and G of Fig. 3, the clarifying capacity of the compart-'ment G- may be somewhat less than it would be if mud to be thickenedand juice to be clarified entered the compartment G through separateinlets such as those provided for in the compartment GA of Fig. '7.

In respect to the features just discussed, the arrangement shown in Fig.9 is like the arrangement shown in Fig. 7 insofar as the primary juiceclarifying unit is concerned, and is like the form of Fig. 3 in respecttothe operation of the secondary juice clarifying unit.

While in accordance with the provisions of the statutes, I haveillustrated and described the best forms of embodiment of my inventionnow known to me, it will be apparent to those skilled in the art thatchanges may be made in the form of the apparatus disclosed withoutdeparting from the spirit of my invention, as set forth in the appendedclaims and that in some cases certain features of my invention may beused to advantage without a corresponding use of other features.

Having now described my invention, what I claim as new and desire tosecure by Letters' Patent is:

1. Apparatus for the compound clarification of liquids having diiferentcharacteristics, comprising a multitray clarifier including a tank. anda plurality of superposed clarifying compartments and two receivingchambers within the tank, said chambers being, respectively above andassociated with upper and lower groups of said compartments, each ofsaid groups comprising one or more of said compartments, and meansconnecting each group and the associated chamber into a separatesedimentation and decantation unit including a fiow path for the downflow of liquid from the chamber into the compartment or compartments ofthe unit. means for separately withdrawing clarified liquid from the twounits, means for separately withdrawing mud from the two units, meansfor passing mud withdrawn from one unit and one or the first mentionedliquids into the receiving chamber of the other unit, means for passingthe clarified liquid withdrawn from the last mentioned unit and thesecond of the first mentioned liquids into the receiving chamber of saidione unit, and a common mud compacting and moving means for the twounits comprising a rotatable, vertical column centrally disposed in ithe tank and mud rake arms carried by said column and extending into thediiferent clarifying compartments.

2. A multi-tray clarifier for effecting compound clarification of twoliquids having diflerent characteristics, comprising in combination atank and partitions therein subdividing the tank interior into tworeceiving chambers and a plurality of superposed clarifying compartmentsiorming two separate sedimentation and decantation units each of whichcomprises one of said receiving chambers andone or more clarifyingcompartments, chambers and compartments for passing one of said liquidsinto the receiving chamber of one of said unitsand for withdrawingclarified liquid from the second of said units and passing it into thelast mentioned receiving chamber and for passing into the receivingchamber of the second or said units the second of said liquids and alsofor passing solids settled out of the liquid-treated in the firstmentioned unit into the last mentioned receiving chamber, and conduitconnections for withdrawing clarified liquid from the first mentionedunit and discharging it from the clarifier and for withdrawing from thesecond of said units solids settled out,oi' the liquid treated thereinand for passing those solids from the clarifier. v

3. A multi-tray clarifier as specified in claim 2, comprising commonmechanism for moving solids accumulating in the lower portion of eachunit to the said conduit connection through which solids are passed fromthe unit.

4. Apparatus for the compound clarification of liquids having difiereritcharacteristics, comprising a multitray clarifier including a, tank anda plurality of superposed clarifying compartments I and two receivingchambers within said tank, said receiving chambers being both above saidcompartments and respectively associated with upper and lower groups ofsaid compartments, .each of said groups comprising one or more of saidcompartments. and means connecting each group and the associated chamberinto a separate sedimentation and decantation unit including a flow.path for the downfiow of liquid from the champrising a multitrayclariifier including a tank and a pluraity of superposed clarifyingcompartments and two receiving chambers within said tank,

said receiving chambers being respectively above g and associated withupper and lower groups of said compartments, each of said groupscomprising one or more of said compartments, and means connecting eachgroup and the associated chamber into a separate sedimentation anddecantetion unit including a flow path for the downflow of liquid fromthe chamber into the compartmentor compartments oi. the unit, means forseparately withdrawing clarified liquid from the two units, uprisingoverflow pipe connections having their discharge ends at approximatelythe same level whereby said connections insure that in normal operationapproximately the same hydro-static pressures will exist in the twoclarified units at every liquid level common to the two units, means forseparately withdrawing mud from the two units, means for passing mudwithdrawn from one unit and one of the first menconduit connections tosaid tioned liquids into the receiving chamber of the other unit, meansfor passing the clarified liquid withdrawn from the last mentionedunitand the second oi-the first mentioned liquids into the receivingchamber of said one unit, and a common mud compacting and moving meansfor the two units comprising a rotatable vertical column centrallydisposed in' the tank and mud rake arms carried by said column andextending into the different clarifying compartments.

6. Apparatus. for the. compound clarification of liquids havingdifierent characteristics, comprising a, multitray clarifier including atank and a plurality'ot superposedclarifying compartments and tworeceiving chambers within said tank, said chambersbeing both above saidcompartments and respectively associated with upper and lower groups'ofsaid compartments, one of said chambers extending circularly about eachofsaid groups-comprising one or more of said compartments, and meansconnecting eachgroup and the associated chamber into a separatesedimentation and decantation unit including a flow path for thedownfiow of liquid from the chamber into the compartment or compartmentsof the unit, means for separately withdrawing clarified liquid from thetwo units, means for separately withdrawing mud from the two units,means for passing mud withdrawn from one unit and one of thefirstcmentioned liquids into the receiving chamber of the other-unit,means'i'or passing the ber into the compartment or compartments oithe'unit, means for separately withdrawing clarified liquid from the twounits, means for separately withdrawing mud from the two units means forpassing mud withdrawn from one unit and one or the first mentionedliquids into the receiving chamber of the other unit, means forpassingthe clarified liquid withdrawn from the last mentioned unit andthe-second of the firstv mentioned liquids into the receiving chamber ofsaid one-unit, and a common mud compacting and moving means for thetwo'units comprising a rotatable vertical column centrally disposed inthe tank and mud rake arms carried by 'said column and extending intothe difierent clarifying compartments.

5. Apparatus for the compound clarification .of liquids havingdifferentrcharacteristics. com-.

clarified liquid withdrawn from the last mentioned unit and the secondof the first mentioned liquids into the receiving chamber of said oneunit, a common mud compacting and moving means for the two unitscomprising a rotatable vertical column centrally disposed in-the tankand mud rake arms carried by said column and extending into thediflerent clarifying compartments, and scum removing means includi acommon scum channel extending above each of said chambers and scumsweeping devices carried and moved by said column and extending intosaid chambers and moving scum collectingtherein. into said channel. 1 v

7. Apparatus for the compound clarification of liquids having difierentcharacteristics, comprising almutlitray clarifier including a tank and aplurality of superposed clarifying compartments and two receivingchambers within said tank, said chambers being respectively above andassociated with 'upper and lower groups of said compartments, each oisaid groups comprising one necting each group and the associated chamberinto a separate sedimentation and decantation unit including a flow pathfor the downfiow of 1iquid from the chamber into the compartment orcompartments oi the unit, means for separately withdrawing clarifiedliquid from the two units, means for separately withdrawing mud from thetwo units, means for passing mud withdrawn from one unit and one of thefirst mentioned liquids into the receiving chamber of the other unit,means for passingthe clarified liquid withdrawn from the last mentionedunit and the second of the first mentioned liquids into the receivingchamber of said one unit, a common mud compacting and moving means forthe two units comprising a rotatable vertical column centrally disposedin the tank and mud rake arms carried by said column and extending intothe different clarifying compartments, and flocculation arms carried bysaid column and extending into said receiving chambers.

8. Apparatus for the compound clarification of liquids havingdiiferentcharacteristics, comprising a multitray clarifier tank structureenclosing a plurality of superposed clarifying compartments and tworeceiving chambers, respectively above and associated with upper andlower groups of said compartments, each of said groups comprising one ormore of said compartments, said structure including superposedpartitions form ing the bottom walls of said chambers and compartmentsexcept the lowermost compartment, and means connecting each group andthe associated chamber into a separate sedimentation and decantationunit including a flow path for the downfiow of liquid from the chamberinto the compartment or compartments of the unit, means for separatelywithdrawing clarified liquid from the two units, means for separatelywithdrawing mud from the two units, means for passing mud withdrawn fromone unit and oneof 1 the first mentioned liquids into the receivingchamber of the other unit, means for passing the clarified liquidwithdrawn from the last mentioned unit and the second of the firstmentioned liquids into the receiving chamber of said one unit, a commonmud compacting and moving means for the two units comprising a rotatablevertical column. centrally disposed in.the tank and mud rake armscarried by said column and opening in the corresponding partition.

9. Apparatus for the compound clarification of liquids having differentcharacteristics, comprising a multitray clarifier including a tank and aplurality of superposed clarifying compartments and two receivingchambers within said tank, said receiving chambers being respectivelyabove and associated with upper and lower groups of said compartments,one of said receiving chambers being coaxial withthe tank and of adiameterless than the tank diameter, and the other of said'chambers'comprising a lower portion of the full diameter of the tank andextending under the firstmentioned chamber and also comprising anuprising portion extending circularly about as'ms'rs or more of saidcompartmentaand means conthe first mentioned chamber, each of saidgroups comprising one or more of said compartments, and means connectingeachgroup and the associated chamber into a separate sedimentation anddecantation unit including a flow path for the downfiow of liquid fromthe chamber into the compartment or compartments of the'unit, means forseparately'withdrawing clarified liquid from the two units, means forseparately withdrawing mud from the two units, means for passing mudwithdrawn from one unit and one of the first mentioned liquids into thereceiving chamber of the other unit, means for passing the clarifiedliquid withdrawn from the last mentioned unit and the second of thefirst mentioned liquids into the receiving chamber of said one unit, anda common mud compacting and moving means for the two units comprising arotatable vertical column centrallydisposed in the tank and mud rakearms carried by said column and extending into the different clarifyingcompartments, said vertical column being formed with channels which areincluded in the connecting means through which liquid flows from the twochambers into the clarifying compartments of the respective-units.

10. Apparatus for the compound clarification of liquids having differentcharacteristics, comprising a multitray clarifler tank structureenclosing a plurality of superposed clarifying com partments, tworeceiving chambers, respectively above and associated with upper andlower groups of said compartments, each of said groups comprising one Ormore of said compartments, said structure including superposedpartitions forming the bottom walls of said chambers and of each of saidcompartments except the lowermost compartment, and means connecting eachgroup and the associated chamber into a separate sedimentation anddecantation unit including a flow path for the downflow of liquid fromthe chamber into the compartment or compartments of the unit, means forseparately withdrawing clarified liquid from the two units, means forseparately withdrawing mud from the two units, means for passing mudwithdrawn from one unit and one of the first mentioned liquids into thereceiving chamber of the other unit, means for passing the clarifiedliquid withdrawn from the last mentioned unit and the second of thefirst mentioned liquids into the receiving chamber of said one unit, acommon mud compacting and moving means for the two units comprising arotatable vertical column centrally disposed in the tank and mud rakearms carried by said column and extending into the different clarifyingcompartments, and means forming a seal between said column and thepartition forming the, bottom wall of the lowermost compartment of saidupper group of compartments operative to substantiall prevent flowbetween the last mentioned compartment and the subjacent tank structurespace through the central opening in the last mentioned partition whenthe difierence between the pressure in the last mentioned compartmentand the pressure in said space is that prevailing in normal operation,and to permit such fiow -when said difference in pressures exceeds thatlatter to form an inverted trough extending circularly about saidcolumn, and the other of which comprises a cylindrical flange extendingoutwardly into said trough, and means for passing air under pressureinto said trough.

12. A multitray clarifier for compound clarification of liquids havingdifferent characteristics, comprising a tank and internal partitionsdividing the tank space into a plurality of sections and comprising aplurality of horizontally extending partition members located atdifferent levels and each separating two of said sections in superposedrelation with one another, said sections being combined to form twoseparate sedimentation and decantation units, each of which comprises aclarifying portion comprising one or more of said sections and areceiving chamber, formed by another of said sections, which is abovesaid clari-' fying portion and is connected to the latter to provide aflow path for the downflow of liquid into the clarifying portion fromsaid receiving chamber, one of said receiving chambers having aperipheral wall extending about the tank axis and spaced inwardly fromthe peripheral wall of the tank and supported by connectlonsbetween saidwalls, and the other of said chambers comprising a lower portion of thefull diameter of the tank and extending under the first mentionedchamber and comprising an uprising portion extending circularly abovethe first mentioned portion between upper and lower levels respectivelyabove the upper edge and below the lower edge of said connections, andconduit connections to said sec.- tions'comprising means forseparatelywithdrawing clarified liquid from each of the sectionsincluded in said clarifying portions, means for separately withdrawingmud from the lower portionof each unit, means for passing mud'withdrawnfrom one unit and one of the first mentioned liquids into the receivingchamber of the other unit, and means for passing the clarified liquidwithdrawn from the last mentioned unit and the second of the firstmentioned liquids into the receiving chamber of said one. unit, saidmeans cooperating to normally maintain said tank space filled withliquid below a liquid level adjacent the upper end of the tank with thehydrostatic pressure of the liquid at any lower level substantiallyproportional to the distance between the two levels whereby the liquidpressures acting against the upper and lower sidesof each of saidpartition members, substantially balance one another.

13. Apparatus for the compound clarification oi liquids having difierentcharacteristics, comprising a multitray clarifier including a pluralityof superposed claril'yin compartments, two receiving chambers,respectively above and associated with upper and lower groups of saidcom- Dflrtments, one of said receiving chambers having a peripheral wallextending about the tank axis and spaced inwardly from the peripheralwall or the tank and supported by connections between said walls and theother of said chambers comprising a lower portion of the full diameterof the .tank and extending under the first mentioned chamber andcomprising an uprising portion extending circularly above the firstmentioned portion between upper and lower levels respectively above theupper edge and below the lower edge of said connection, each of saidgroups comprising one or more of said compartments, and means connectingeach group and the associated chamberinto a separate sedimentation anddecantation unit including a flow path for the downflow of liquid fromthe chamber into the compartment or comprising a rotatable verticalcolumn centrally disposed in the tank, mud rake arms carried by saidcolumn and extending into the different clarifying compartments, andscum removing means carried by said column and respectively extendingover and under said connections.

14. A inultitray clarifier for compound clarification of'liquids havingdifferent characteristics, comprising a tank and internal partitionsdividing the tank space into a plurality of sections and comprising aplurality of horizontally extending partition members located atdifferent levels and each separating two of said sections in superposedrelation with one another, said sections being combined to form twoseparate sedimentation and decantation units, each of which comprises aclarifying portion comprising one or more of said sections and areceiving chamber formed by another of said sections which is above-saidclarii'ying portion and is connected to the latter to provide a flowpath for the downflow of liquid into the clarifying portion from saidreceiving chamber, and conduit connections to said sections comprisingmeans for separately withdrawing clarified liquid from each of thesections included in said clarifying portions, means for separatelywithdrawing mud from the lower portion of each unit, means for passingmud withdrawn from one unit and one of the first mentioned liquids intothe receiving chamber of the other unit, means for passing the clarifiedliquid withdrawn from the last mentioned unit and the second of thefirst mentioned liquids into the receiving chamber of said one unit-saidmeans cooperating to normally maintain said tank space filled withliquid below a liquid level adjacent the upper end center columnextending through said partition members and formed with verticallyextending channels separately connecting the receiving chambers of thetwo to the clarifying portions thereof and thereby providing the saidflow path of each unit.

- WILLIAM E. GEISSLER.

